188 Miscellanies. 
phosphorus—a substance which, in contact with the most delicate 
thermometer, affords no indication of heat. Phosphorus has been 
cited as an example of the disengagement of light unattended by 
caloric : we see, therefore, that the supposed separation of these two 
agents is not real. With respect to the temperature of the luminous 
rays of the moon, the different means we have adopted in order to 
decide upon this subject have not completely succeeded ; but we 
think that we are able to assert, that, if the rays of the moon really 
possess a peculiar temperature, it cannot happen except to a Santee 
of a degree excessively small. 
The thermo-multiplier, possesses many advantages in detoniiaeds 
the reflecting powers of different surfaces. Our experiments prove 
that Mercury i is the best reflector of caloric: after which, come cop- — 
per and the other metals, in the order indicated by Leslie. Polishing 
increases the power xf Bi sesies oes toa ensich less a than is 
ordinarily supposed. Non. y pow- 
er of reflecting heat, whatever may be the nature of their silabeaal 
The method which we employed for ascertaining the absorbing 
powers of different bodies, is very simple. The whatenbeal upon 
which we wish to experiment, are attached to equal disks of sheet-tin, — 
to the opposite side of which is attached a stem, perpendicularly from 
its centre. The substances are exposed for several minutes to: 
rays of the sun, and are then presented to the instrument. By ope- 
rating thus, we do not obtain results absolutely free from error ;~but- 
we learn with a high degree of precision, whether one surface has a 
higher absorbing power than anetine lows the 
experiments =- mo 
In the first place, we kata to assure es oes So r, what 
s So long been admitted, the state and the color of surfaces have _ 
any influence upon the absorbing power. In order to resolye the first 
of these questions, we manigiccd two metallic disks, one in its natural 
state, the other was covered with furrows or scratches: the motion 
of the needle took place constantly from the side of the furrowed disk. 
As to the second question, we could not resolve it directly, since in 
altering the color of a surface, we necessarily alter the chemical na- 
ture of the surface which composes it. It was necessary therefore 
to resort to an indirect solution. With this view, we colored many 
pair of disks black, or white, with all sorts of vegetable and min- ae 
eral pigments; we covered others with layers of marble or of wool 
with fabrics of silk, wool wool and cotton. The absorption was always — 
